Chord progression inspired singing

I recently used scaler to find chord progression of many popular songs
I found that most chord progression is not difficult
It can even be said that there are only a few
But why can’t I sing?
But they can sing so well through such a simple chord progression
I wonder if there are any skills in it
In fact, I often get up in the morning to open scaler and play chord progression
Sometimes I sing some nice songs
But it soon disappeared :sweat_smile: